Hurricane Hermine is forecast to make landfall tomorrow morning along the eastern Florida panhandle, and Gulf of Mexico oil and gas operators have been evacuating rigs and platforms and activating shut-in procedures in preparation.

Based on estimates drawn from operator reports, approximately 15% of the current oil production in the Gulf of Mexico has been shut-in as of Sept. 1, along with roughly 9% of natural gas production. Shut-in procedures close the sub-surface safety valves located below the surface of the ocean floor to prevent the release of oil or gas in a storm.

As of 11:30 a.m. CDT on Sept. 1, the Bureau of Safety and Environmental Enforcement (BSEE) said that personnel have been evacuated from 10 of the 750 manned production platforms in the Gulf of Mexico.

Drilling rigs — generally more mobile than production facilities — are being evacuated or moved off location, the BSEE said. One non-dynamically positioned rig had been evacuated as of Sept. 1, while three dynamically positioned rigs have been moved out of the storm’s path as a precaution. Personnel will remain on board those rigs and return to the location once the storm has passed.

BSEE said the agency would continue to issue regular updates as appropriate, and that standard inspections would be conducted after the storm to bring facilities back online.